稻草覆盖和香根草篱联合调控红壤坡耕地土壤团聚体粒组碳钾分配规律

土壤有机碳可以通过影响土壤矿物钾释放以及解钾菌特性而对土壤钾素产生影响，本文基于稻草覆盖和香根草篱控制红壤坡耕地水土流失长期定位试验，通过对比常规管理(CK)、稻草覆盖(S)、稻草覆盖+香根草篱 (S+V)处理，研究稻草覆盖及香根草篱措施对土壤主要化学性质的影响，并分析土壤团聚体粒组分布及碳和钾在土壤团聚体粒组中的分配规律。结果表明，在所有处理中，S+V处理的土壤pH、有机碳、全钾和速效钾含量显著较高，与CK处理相比，S+V处理的土壤pH提高了0.23，有机碳、全钾和速效钾含量分别提高了6.52%、11.60% 和11.49%。不同处理下土壤团聚体粒组分布无显著差异，所有土壤团聚体粒组中均以>0.25 mm土壤团聚体粒组的比例最高。与CK处理相比，S和S+V处理的 >2 mm土壤团聚体粒组有机碳含量分别提高了9.42% 和40.03%。与CK处理相比，S+V处理下 >2 mm、0.25 ~ 0.053 mm和 <0.053 mm土壤团聚体粒组中全钾含量分别提高了3.67%、4.92% 和5.14%。同时，S+V处理下 >2 mm和 <0.053 mm土壤团聚体粒组中速效钾含量分别比CK处理增加了20.10% 和12.28%。因此，在红壤坡耕地上，稻草覆盖和香根草篱联合措施是有效改善土壤团聚体粒组碳钾分配的水保措施，一方面提升了>2 mm土壤团聚体粒组的有机碳含量，另一方面也显著增加了>2 mm和 <0.053 mm土壤团聚体粒组的速效钾含量，从而有利于维持土壤结构，为保障作物高产奠定基础。

Regulation of Carbon and Potassium Distribution in Soil Aggregates of Red Soil Slope Farmland by Rice Straw Mulching and Vetiver Hedgerow

Soil organic carbon can affect soil potassium by affecting the release of soil mineral potassium and the characteristics of potassium dissolving bacteria. Therefore, in this paper, based on the long-term positioning experiment of rice straw mulching and vetiver hedgerow to control soil and water loss in red soil slope farmland, by comparing conventional management (CK), rice straw mulching (S), rice straw mulching and vetiver hedgerow (S+V), the effects of rice straw mulching and vetiver hedgerow measures on soil main chemical properties were studied, and the distribution of soil aggregates and the distribution of carbon and potassium in soil aggregates were analyzed. The results showed that soil pH, organic carbon, total potassium and available potassium were significantly higher under S+V than CK and S, compared with CK, which were increased by 0.23 units, 6.52%, 11.60% and 11.49% respectively. No significant difference was found in the distribution of soil aggregates under different treatments, and the proportion of soil aggregates >0.25 mm was the highest among all soil aggregate components. Compared with CK, the organic carbon content of >2 mm soil aggregates were increased by 9.42% and 40.03% under S and S+V, respectively, meanwhile, the contents of total potassium in soil aggregates and >2 mm, 0.25-0.053 mm and <0.053 mm were increased by 3.67%, 4.92% and 5.14%, and the contents of available potassium in soil aggregates >2 mm and <0.053 mm were increased by 20.10% and 12.28% under S+V, respectively. Therefore, on the red soil slope farmland, the combined measures of straw mulching and vetiver hedgerow are effective soil conservation measures to improve carbon and potassium distribution of soil aggregate components, which improved organic carbon content of >2 mm soil aggregates and significantly increased available potassium content of >2 mm and <0.053 mm soil aggregates, thus is conducive to maintaining soil structure and ensuring high yield of crops.